Mail processing systems, such as, for example, mailing machines, inserters and the like, often include different modules that automate the processes of producing mail pieces. The typical mail processing system includes a variety of different modules or sub-systems each of which performs a different task on the mail piece. The mail piece is conveyed downstream utilizing a transport mechanism, such as rollers or a belt, to each of the modules. Such modules could include, for example, a singulating module, i.e., separating a stack of mail pieces such that the mail pieces are conveyed one at a time along the transport path, a stripping/moistening module, i.e., stripping open the flap of an envelope, wetting and sealing the glued flap of an envelope, a weighing module, and a metering/printing module, i.e., applying evidence of postage to the mail piece. The exact configuration of the mail processing system is, of course, particular to the needs of the user.
The stripping/moistening module includes a stripping blade for separating a flap of a moving envelope away from the envelope's body to enable the moistening and sealing process to occur. The stripping blade becomes inserted between the flap of the envelope and the body of the envelope as the envelope traverses the transport deck of the mailing machine. Once the flap has been opened, the moistening device moistens the glue line on the flap in preparation for sealing the envelope. One type of moistening system, known as a contact moistening system, generally deposits a moistening fluid, such as, for example, water or water with a biocide, onto the glue line on a flap of an envelope by contacting the glue line with a wetted applicator.
FIG. 1 illustrates a conventional stripper/moistening device 8. An applicator 10, typically formed from a contact media such as a brush, foam or felt, is held by a rigid support 12 that is secured the trailing edge 14 of the stripping blade 16. The applicator 10 is supplied with moistening fluid, either through physical contact with a wick (not shown), a portion of which is located in a reservoir containing the moistening fluid (not shown), or via a pump system and tubing (not shown). As an envelope, with the side having the flap facing down, is guided over the stripping/moistening device 8, the envelope body will pass over the top of the stripping blade 16 and support 12 while the envelope flap will pass under the stripping blade 16 and support 12. The inside of the envelope flap, where the glue line for sealing the flap is located, contacts the applicator 10, such that the applicator 10 transfers moistening fluid to the flap to activate the glue. The flap is then closed and sealed, such as, for example, by passing the closed envelope through a nip of a sealer roller to compress the envelope and flap together, and the envelope passed to the next module for continued processing.
There are problems, however, with conventional stripping/moistening modules as described above. For example, efficient sealing of the envelope flap is dependent upon the envelope flap making sufficient contact with the applicator to allow sufficient moistening fluid to be transferred from the applicator to the glue line on the envelope flap. If the glue line on the envelope flap does not receive sufficient moistening fluid, the glue will not activate and the flap will not seal. In many instances, the envelope flaps can buckle and pull away from the applicator, causing an insufficient amount of moistening fluid to be applied along the glue line on the flap. This is especially true of envelopes that include numerous inserts, i.e., thick mail pieces. FIG. 2 illustrates a cross-sectional view of the device 8 taken along line A-A′ in FIG. 1 (perpendicular to mail flow) while a thick mail piece 20 is being processed. Thus, in FIG. 2, the mail piece 20 is moving in a direction out of the page. The mail piece 20 includes an envelope body 22, a flap 24, and contents 26. As can be seen from FIG. 2, the flap 24 is required to bend around the thickness of the contents 26, the support 12 and the applicator 10. Each of these elements effectively act as a wedge, forcing the envelope flap 24 away from the body 22. The amount of bending required increases as the thickness of these elements increases. Thus, as the thickness of the contents 26 of the mail piece 20 increases, the amount of bending required also increases. The amount of bending is also dependent upon the size of the flap. As the flap increases in size, the amount of bending required also increases. The bending of the flap 24 creates multiple contact points 28 between the flap 24 and the support 12, and the flap 24 and applicator 10. The contact points 28, in turn, force the envelope flap 24 further open in the direction indicated by arrows 30 due to the beam strength of the flap 24. This results in a loss of contact between the glue line 32 of the flap 24 and the applicator 10. In addition, differences in linear velocity between the flap 24 and envelope body 22, caused by the flap 24 having to move around the applicator 10 and support 12, cause the flap 24 to buckle along and perpendicular to the direction of movement of the mail piece 20. This buckling also causes a loss of contact between the glue line 32 of the flap 24 and the applicator 10.
The loss of contact between the glue line 32 of the flap 24 and applicator 10 results in the glue line 32 not receiving sufficient moistening fluid from the applicator 10 to activate the glue, and thus the flap 24 will not properly seal to the body 22. As the thickness of the mail piece increases, the amount of contact decreases, therefore making it difficult to reliably seal thick mail pieces. These problems are further exacerbated by the fact that envelopes are increasingly available in a variety of sizes with differently shaped flaps, and the different shapes can each be provided in different sizes. Thus, there exists a need for a moistening system that can better accommodate thick mail pieces and larger flaps to ensure reliable sealing.